IX:2 Refrain from sexual abuse (Seyyasaka)

Once there was a monk by the name of Seyyasaka, who was not happy with the religious
life and was in the habit of stimulating himself sexually. When the Buddha heard
about this, he admonished the monk to refrain from acts that would lead him farther
away from the gaining of purity. At the same time, the Buddha introduced the disciplinary
rule for bhikkhus to abstain from such indulgence in sensual pleasure. He called
them offences which require censure. Then, the Buddha added, 'This kind of act can
lead to suffering.'